Metallic cap provided with a separate bottom disc



May 27, 1969 A. PODESTA ET AL 3,446,381

METALLIC CAP PROVIDED WITH A SEPARATE BOTTOM DISC Original Filed May 19, 1966 Sheet of 2 May 27, 1969 PODESTA' ET AL 3,446,381

METALLIC CAP PROVIDED WITH A SEPARATE BOTTOM DISC Original Filed May 19, 1966 Sheet 2 of 2 US. Cl. 215-40 Claims ABSTRACT OF THE DISCLOSURE A two piece metallic cap for the closure of a container including a bottom disc with a peripheral edge projecting from the peripheral outer edge of the container mouth, and a sleeve like skirt provided with an inturned flange at its top with means for securing it to the container mouth; the edge of the inturned flange cooperates with the projecting peripheral edge of the bottom disc to compress the disc against the mouth of the container.

This application is a continuation of application Ser. No. 551,319, filed May 19, 1966, and now abandoned.

This invention relates to two-piece metallic caps for the closure of containers, particularly of glass bottles, pots and like containers provided with a cylindrical top or neck ending with a circular mouth. The invention aims to provide improved caps for such containers including a sleeve which may be anchored by screwing to the container neck and a bottom disc which is separated from said sleeve and pressed against the mouth with the interposition of a suitable packing, by a small inturned flange projecting from the top sleeve edge and which co-acts with the outer marginal part of the said bottom disc.

With respect to the single-piece closure caps provided with a depending side skirt integral on its bottom i.e. formed in one piece with said bottom, the two-piece caps, the bottom of which is formed by a separate disc, present the advantage that when they are fitted upon the mouth, the rotation of the sleeve by fastening of the cap is not transmitted to the cap bottom, so that the slipping of the packing upon the container mouth is avoided and thus damaging of the packing due to friction is prevented.

In known caps provided with a separated bottom disc, the inturned flange of the top edge of the sleeve acts upon the bottom disc in correspondence with the annular surface of the mouth end, i.e. it bears against the bottom inside of the outer perimeter of the said mouth. Consequently the marginal part of the bottom, which is compressed by the sleeve upon the mouth surface cannot correct the irregularities of said top surface which, especially in glass containers, may comprise surfaces at different levels. In order to compensate for such irregularities, the packing of the known caps provided with a separate bottom disc must present a relatively great thickness, which means a correspondingly increase of the cost. Furthermore the sleeve must be screwed with great force in order to obtain the necessary considerable compression of the bottom disc and of the packing upon the mouth. The pressures of such order are however difficult to obtain by automatic capping machines and furthermore they render the screwing of the cap less easy and the tightness is not always perfect.

States Patent The invention aims to obviate said inconveniences by providing a cap comprising a sleeve part provided with a very narrow inturned flange at the top end, which does not project above the underlying container to be capped, while the underlying bottom disc projects under the flange edge and has thus a greater diameter than the outer edge of the mouth of the container to be capped.

With this arrangement, the bottom disc packing is pressed against the mouth through a certain lever arm and furthermore the pressure zone of the bottom disc upon the mouth is shifted towards the exterior, thus compelling the packing to effect its seal in correspondence with the outer mouth edge.

Therefore, and due to the fact that the part of the bottom disc which coacts with the container mouth is not directly engaged by the upper inturned sleeve flange and therefore is not hindered in its deformation, the bottom disc may freely and readily adapt itself to the irregularities of the mouth. Consequently packings having a very reduced thickness and cost may be employed.

Furthermore, due to the considerably limited compression surface of the packing (said surface being limited to the outer mouth edge) a high specific pressure and consequently a perfect tightness may be obtained, by employing a very reduced screwing force, thus facilitating both the closure and opening operations and enhancing the use of automatic capping machines.

A particularly advantageous embodiment of the twopiece cap according to the invention and also a particularly simple and practically wasteless manufacturing meth- 0d of same will be described hereinafter with reference to the accompanying drawings, in which:

FIGURES 1 and 2 show in a somewhat enlarged scale and in a partial vertical section a preferred embodiment of a two-piece cap according to the invention, before and after its fitting upon a container mouth.

FIGURES 3, 4 and 5 show diagrammatically in vertical section the three successive steps of a preferred method and means for the manufacture of the cap as shown in FIGURES 1 and 2.

FIGURE 6 shows in plan view the in-pressed halfworked blank which is obtained in the working step shown in FIGURE 4.

With reference to FIGURES 1 and 2, the two-piece metallic cap according to a preferred embodiment of the invention, comprises a bottom disc 1 and a sleeve 2 to be anchored by means of a curled edge 5 provided with a flattened inclined top to complementary screw thread sections 4 of the container neck 3. These anchoring elements of caps and container necks are known per se and need not be described in detail.

The bottom disc 1 has a diameter which is greater than the outer diameter of the container mouth 3 and therefore it projects with its peripheral part 101, which is preferably slightly bent downwardly, for a certain length outside of the containers outer mouth edge. Under the bottom disc 1 an annular packing 6 is provided which also extends beyond the container mouth edge.

Sleeve 2 has a substantially cylindrical lower section 102 which, through an annular, preferably slightly conical step 202, is connected to a substantially cylindrical or preferably slightly reversed conical top part 302 having a smaller diameter than the lower sleeve part. The top edge of sleeve 2 is in-turned and then bent over itself downwardly and towards the outside, so as to form a narrow double-thickness inturned flange 7, whose stiffness is considerable and whose internal diameter is greater than the diameter of the outer edge of the container mouth. The inside diameter of the top part 302 of sleeve 2, immediately below flange 7, is substantially equal or slightly in excess of the outer diameter of the bottom disc 1, while the diameter of the part just below the edge of the bottom disc 1 is preferably restricted so as to trap the disc 1 under said flange. This restriction can be etfected by conventional means, such as in-pressing, or by making said sleeve part inversely conical.

Under the above-outlined conditions, when the cap is fitted on to the mouth 3 by screwing sleeve 2 upon the outer projecting part 4 of the neck, the in-turned top flange 7 of sleeve 3 bears against and compresses the marginal part of the bottom disc 1, with the interposition of the packing 6 upon the edge of the container mouth.

Since the flange 7 is very narrow and bears upon the peripheral part 101 of bottom disc 1 beyond the container mouth edge (see FIGURE 2), the bottom disc 1 being peripherally pressed downwardly by the flange 7 resiliently bears with its packing 5 upon the outer edge of the mouth, viz. upon a very restricted area. Consequently considerable specific pressures might be exercized upon the packing by means of a reduced total pressure upon the bottom disc, and with a very reduced screwing force upon sleeve 2. This force is further reduced due to the lever arm existing between the bearing circle of flange 7 upon the projecting peripheral part 101 of the bottom disc 1 and the outer edge of mouthpiece 3.

At the same time, the marginal part of bottom disc 1, by superposing itself to the edge of the mouthpiece 3 is freely deformed and the underlying packing adapts itself perfectly to the irregularities of the container mouth. Furthermore, due to the inside diameter of sleeve 2 being, both in its lower part 102 and in its top part 302 considerably greater than the outside diameter of the mouthpiece 3, the cap according to the invention may perfectly fit ovalized container mouths.

This just described cap may be manufactured preferably by the method and means as shown in FIGURES 1 through 6.

For the manufacture of the cap, a disc-shaped fiat sheet-metal blank is employed as starting material. This =blank (not shown) is first cupped so as to form a conventional cap C, having a substantially cylindrical skirt and afterwards, in the bottom thereof, a certain distance inside of its outer top edge, a discontinuous circular cut T is made, for example by means of tool A, as diagrammatically shown in the right half of FIGURE 3, which forms a bottom disc 1 connected to a narrow inturned flange by narrow strips S (FIGURE 6).

In the second working step, as shown in FIGURE 4, the diameter of the top part 302 of skirt 2 is reduced so as to cause this top part 302 of the skirt to stick or almost stick from the exterior to the peripheral edge of the bottom disc 1 and to form the conical step 202 of the skirt 2. The said top part is restricted, or has a restricted section under the edge of disc 1. At the same time, the inside flange 107 formed at the top edge of the in-pressed cap C in the preceding working step, after the execution of the circular cut T, is superposed to the marginal part of bottom disc 1 and is folded upon itself, so as to form the inturned top flange 7 of lateral skirt 2. These operations are effected preferably simultaneously, for example by means of the forming and folding tool B which has been diagrammatically shown at the right-hand half of FIGURE 4.

During such operation, the thin connecting strips S between bottom disc 1 and skirt 2 are automatically torn off so that this latter constitutes a separate sleeve. Although the bottom disc 1 is completely Severed from the sleeve 2, it remains however trapped therein due to the in u ned flange 7 which is superposed to he mar- 4 ginal part of the bottom disc and the restricted part of the skirt below the disc edge.

The cap thus obtained may be again easily transported as a whole to the successive working station, Where the inside curling on the lower edge of said sleeve 2 is effected by means of a tool D having a curved projecting edge D, as diagrammatically shown in the righthand half of FIGURE 5. At the Same time with this curling, also the top part of the skirt 2 is deformed, so as to impart a slight inverted conicity thereto. This conical deformation of the top part 302 of sleeve 2 may be easily obtained at the same time of the lower curling by means of a suitable shaping of the guide surfaces of the curling tool D.

It is apparent that the abovedescribed process according to the invention, besides having the above-mentioned advantages, permits also the manufacture of caps provided with a separate bottom disc even on completely automatic production lines.

Of course, the invention is not limited to examples of embodiments as above described and shown, but may be amply varied and modified as regards both the realization of the cap and the means and process for the manufacture thereof.

We claim:

1. A two piece metallic cap for closing a container mouth comprising a disc having a peripheral edge adapted to project beyond the edge of the container mouth; a sleeve having a top portion, a bottom portion of larger diameter than the top portion, and an annular step portion connecting said top and bottom portions, said top portion having a frusto-conical shape defined by a small base with a diameter smaller than said disc and a larger base with a diameter larger than said disc whereby said disc is entrapped in the top portion of said sleeve, said top portion having an inturned flange at its top edge projecting slightly beyond the peripheral edge of said disc, and said bottom portion having screw-threaded sections at its lower edge adapted to coact with anchoring screw threads on the container whereby threading of said bottom portion causes said inturned flange to force th peripheral edge of said disc against the container mouth.

2. A two piece cap for closing a container mouth comprising a continuous disc member dimensioned to span the mouth of the container and project a short distance beyond the edge of the container mouth and a backing on the underside of the disc member in the portion extending from the diameter of the container mouth and beyond, and a sleeve member having a top portion, a bottom portion of larger diameter than the top portion and an intermediate stepped portion connecting the top and bottom portions, the top portion being dimensioned to have a diameter greater than the outer diameter of the container mouth to provide an annular space therebetween, an annular flange extending inwardly from the upper edge of the top portion for a distance to extend beyond the outer peripheral edge portion of the disc member but short of the outer diameter of the container mouth, and means on the bottom portion of the sleeve for coaction with means on the container for holding the sleeve on the container with the flange bearing on the peripheral edge of the disc member to force the latter into sealing engagement with the container mouth.

3. A two piece cap as claimed in claim 2 in which the intermediate stepped portion is of frusto-conical shape having a lower base of smaller dimension that the disc member and an upper portion of larger diameter than the disc member to entrap the disc member therebetween.

4. A two piece cap as claimed in claim 2 in which the peripheral edge portion of the disc member is formed with a slight downward bend.

5. A two piece cap as claimed in claim 2 in which the flanged portion extending inwardly from the-upper edge of the top portion is turned inwardly substantially perpendicularly from the top portion and then doubled 5 6 back under to provide a flanged portion of considerable 2,288,349 6/1942 Gibbs 21544 XR stiffness.

FOREIGN PATENTS Refereuces Cited 435,125 3/1948 Italy. UNITED STATES PATENTS 5 1,137,725 4/1915 Carvalho' DONALD F. NORTON, Przmary Exammer. 2,008,593 7/1935 Pedersen 215-97 2,130,746 9/1938 Scofield 21540 215 97 2,148,169 2/1939 Merolle 215-44 XR 

